Apparatus for drying metallic articles



May l, 1945. A. |y BUNTING ET AL 2,375,173

n APIARATUS FOR DRYING METALLIC ARTICLES Filed April 10, 1942 4Sheets-Sheet l f my ff 21 TTORNE Ys.

May l, i945 A L BUNTINGFET AL 2,37573 APPARTUS FOR DRYING METALLICARTICLES Y Filed April 10, 1942 4 sheefshe'ef 2 NVENTORS. vizi? JA/MATTORNE Ys.

May l, 194.5-4 A. L. BUNTING E1- AL 2,375,173

n APPARATUS FOR DRYING METALLIC ARTICLES Filed April 1o, 1942 4sheets-sheet s T T ORNE 17'5.

May l, l1945.

lA. l.. BUNTING ETAL APPARATUS FOR DRYING METALLIC ARTICLES 4Sheets-Sheet 4 Filed April lO, 1942 LRS.

`atented ay l, w45

sA'rss- AENT,

APPARATUS Foa -pierino. Mamme Aa'rioms .Alberta Bunting, Dearborn, andArthur c. Schultz, Detroit, Mich.; said Schultz assignor to said BuntingApplication April 10, 1942, Serial No.`f138,408

i claim. i(ci. :ii-69)' The present invention relates to apparatus fordrying metallic articles, relating more particularly to apparatus `forbakingA or hardening protective coatings onL articles fabricated .from ymetals subject to rusting or corrosion.

T11-applying most protective coatings to articles y formed of steel orsimilar metals subject to cor- Coatings completely satisfying all of theafore A said conditions have not been produced to date chley because ofineffective or faulty coating apparatus-especially because ofineffective or faulty baking and drying operations attempted to becarried out by such apparatus.

It is, therefore, one object of the present in. vention to provideimproved apparatus for drying metallic articles, said apparatus beingadapted to eiectively air dry and/or bake coate ings such, for instance,as coatings comprising polymerized resinous products or enamel-likecoatings for protecting articles subject to rusting or corrosion.

Itis another object of the invention to provide apparatus of theaforesaid general character in which an air-drying operation may befollowed by a baking operation, both of these operations beingadjustable and controllable in an improved manner, especially as totemperatures and times of treatment, in order that the 'optimumconditions maybe provided for' the particular coating utilized.

Another object of the invention is to provide apparatus for air dryingand/or baking protective coatings for the aforesaid articles and whichis adapted to provide an even, smooth finish coating, free fromwrinkles, sags and blisters and to provide such a finish Coating whetherthe initial .coating material utilized prior to the drying Other objectsand advantages of this inv en tion `will appear in the followingdescription and appended.claim, reference being had to the accompanying.drawings'forming a part of this speciilcation,l wherein like referencecharacters designate corresponding parts in the several views.

. In said drawings: v r

Fig. 1 is'a side elevation of one form of appal ratus embodying ltherpresent invention. For

present purposes, that portion of the apparatus shown at the right sideof Fig. 1 is referred to as the front of the apparatus, while thatportion shown at'the left side of Fig. 1 is designated as the rear. y v

Fig. 2 is a partial'cross-sectional view taken along the line 2--2 ofFig. l in the direction.

of the arrows, parts being broken away to show the interior of theapparatus.

Figs. 3 and 4 are, respectively, front and rear elevational views-of theform of the apparatus shown in Fig. 1. l

Fig. v5 is la sideI elevation of a part of the apparatus shown in Fig.1, but shows the opposite side from that-shown in Fig. 1.4

" Fig. 6 is a detailed view of a part of the air 'tunnel utilized inconnection with the present invention and shows in particular one formof a device for removing 'drops from the article to be I shows a'modiiication of 'the device shown in Fig. 6.

Fig. 9 is a cross-sectional view taken along the the apparatus showingone. form of mechanism for automatically dipping the metallic articles.

15 is aview similar to Fig. 14 but showing another form of automaticdipping mechanism.

" Before explaining in detaill the present invention it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated intheaccompanying drawings, since the invention is capable of otherembodiments and of beingprac-l ticed or carried out in various ways.Also it is to A be understood that the phraseology or terminologyemployed herein is for the'purpose of description and not of limitation.v.

For convenience in understanding, at the outset,

' the principal elements of the embodiment of the invention shown in thedrawings, a. brief general explanation of these elements follows,details .thereof being set forth hereinafter. Referring to saiddrawings, and especially to Fig. l, the reference numeral 2t) indicatesan inclined air-drying enclosure or tunnel which opens at its upper orinner end into a generally vertically positioned enwith the air-dryingoperation.

closure or chamber 2l also utilized in connection The reference numeral22 indicates in general an oven utilized for the baking operation. Asbest shown in Fig. 2,

the oven 22 is separated from the chamber 2| by a suitable partition 23and communicates with said l oven by means of an opening 24 extendingacross the width of the oven and the chamber 2|, said opening beingpositioned near the bottom of the apparatus. The oven 22. is heated byhot air supplied by a heating and blowing unit indicated in general bythe reference numeral (Figs. 3 and 4), the hotl air supplied by saidunit being-con ducted to the oven by means of a duct 26. As best4 shownin Fig. 1, a continuous chain conveyor is provided in the apparatus andis adapted to conduct the articles to be coated through the air-dryingtunnel 20, the chamber 2i and thence through the oven 22, After being soconducted through the air-drying tunnel, the chamber and the oven,

` the articles are conducted by the chain conveying system out ,of theoven at the rear of the apparatus (see Fig. 4) and may then be removedfrom the apparatus. Thevarious devices shown in Figs. 6 to 13 inclusivefor removing drops from the objects to be coated are positioned vin theair tunnel 2|) preferably, but not necessarily, at the lower front endthereof. The structure and operation ofthese `devices is explained fullyhereinafter. A

Referring to the aforesaid apparatus in greater detail, the air-dryingtunnel 20 is dimensioned and shaped to receive the object or objects tobe coated. For instance, in the form ci' the invention shownv in 'theaccompanying drawings the air tunnel 20 is generally rectangular incross section as best shown in Fig. 2 and its height is arranged so thatthe ice trays 21 may be received 'within the tunnel 25 and carriedtherethrough by the chain conveyor system explained hereinafter. Vwidthof the air tlmnel 23 is such that a plurality The 'of these ice traysmay extend across the width of the tunnelin the manner clearly indicatedin the drawings in Figs. 3 andl 4. The air tunnel 20 is` gether andseparated by suitable generally verti-A cally positicned spaced sideangle irons or supports 33-33.- Inthe particular form of the tunnel 2|J`shown in the drawings, especially Fig. 2, it will be lnoted that thebottom member, is placed over the .lower supporting longitudinal angleiron v32- 32 so'that the side angle iron 33-33 extends through openingsinthe bottonrmember 3|).- We` have found this to be a'desirableconstruction and it will be understood that the tunnel 20 may bev formedof suitable top, side and bottom members supported by and attached to asuitable frame work in several satisfactory ways which will readf ilyoccur to one skilled in the art.

The entire tunnel structure 20 comprising top, side and bottom members28, 29 and 30 and the framework consisting of the angle irons 3|, 32 and33, is supported by a suitable supporting framework in the manner bestindicated in Fig'l. As there shown, this supporting lframework comprisesgenerally longitudinal horizontally extending side frame members 36 towhich is fixed a number of spaced generally upright supporting members35 which are also fixed to the bottom supporting rail 32 of the tunnel2li. As indicated in Fig. l. the supporting members 35 are so arrangedwith respect to their height that the tunnel 20 is maintained at anupward inclination.

The tunnel 20 communicates with or leads into the generally uprightenclosure or chamber 2 I. This chamber 2| is formed by side panels 36and 31 (Figs. 1 and 5) formed of sheet metal or thelike. The front ofthe chamber or enclosure 2| comprises a generally similar panel 38 (Fig.2) and the rear of the chamber 2| is formed by a similar panel 23 whichseparates the chamber 2| from the oven 22. As pointed out hereinbeiore,this partition does not extend to the bottom of the device, therebyproviding an opening 24 to permit;J communication between the oven 22,chamber 2| and tunnel 2i).A As best indicated in Figs. 2 and 5, the sidewalls 36 and 31 are supported by and attached to supporting members 35(Fig. 2) at the front and to generally similar supportingmembers 39(Figsrl and 5) at the rear. The front panel extends between the spacedmembers 35-35 (Fig. 2) while the rear panel extends between the spacedmembers 39-39. The top of the chamber is closed by a suitable top membershown at #0 (Figs. 1 and'). As indicated in the drawings and inparticular in Fig. l, the framework for'the enclosure 2| is supported byand is attached to the longitudinally extending rails 36-34.

The oven 22A includes of angle irons or generally similar supportingmembers and the laterally spaced members f 39?-39 form the front uprightmembers of this framework. These members are attached to suitablelongitudinally parallel and spaced bottom frame members lil-5|. At therear of the oven thereis provided a pair of laterally spaced uprightframe members 42--52 (Fig. 4) and a pair of top frame members 43-'43(Figs. l and 5) extendingbetween theupright frame members 39 and 40completes the outline of this framework. Suitable cross frame memberssuch as 1 those shown at M- (Fig. i) may be utilized to apparatus in themanner indicated hereinafter. e The oven is enclosed by'providing sheetmetal to form lthe front wall of the oven and separatev strengthen theframework and for the purpose of attaching various working parts of thepresentsides 45 and 48 and the partition or ,wall 23 serves the ovenfrom the enclosure or chamber 2| in they manner indicated hereinbefore.

-As best shown in Figs. l and 5f the oven22 is formed at the rear to'provide a stepped section indicated in general at "J This section 41 isformed of suitable sheet metal side and end pieces supported by andattached to suitable frame members in 'the same general manner as the Aother side and endpieces of. the oven described in detailhereinbefore.As also shown in Figs. 1

' and 5, the top of the stepped section is left open..

a framework consisting I In fact ka portion of the stepped section shownat 48 provides-an open top part for the chain `conveyor system explainedhereinafter to emerge from the oven and the open top part of the stepped4section shown at 49 permits the chain conveyor system to reenter theapparatus. The objects carried through the apparatus by the chainconveyor system may be removed from the apparatus when they have beencarried down the chain conveyor after it has emerged from the pointmarked 138 and before it reaches the point marked' 49.

Referring in greater detail to this chain conveyor system, it will benoted that itl is arranged on sprockets placed throughout the device.This chain conveyor system in general possesses two continuous parallelspaced chains running over the sprockets, said chains being connected bybars or supports from which the objects to be carried through theapparatus are hung or suspend.

ed in the manner best shown in Fig. 3. Thus, this chain conveyorcomprises chains 50 and 5| running over suitable sprockets not shown) inthe air tunnel 20, continuing through the tunnel and over a sprocket 52located at the top thereof. After passing over the sprocket 52 the chainconveyor continues downwardly throughout the chamber 2i, passes over thesprocket 53 and thence over a series of sprockets arranged so that thechain conveyor passes up and down several times through the oven in themanner clearly shown in Fig. l. After passing about the last sprocket inthe'oven, which is the sprocket shown at 5t. the chain conveyor passesaround the sprocket 55 which` is located immediately above the openingi8 whereby the chain emerges from the oven, passes about the sprocket 55down through the opening shown at t8 and thence about the sprocket 56.lThereafter it continues in the manner clearly shown in Fig. 1 until itagain passes around the sprocket 52 whereupon the cycle is repeated.It.will be understood that this chain is a continuous system.. Thechains 5B and 5l are kept taut by a spring sprocket shown at 5l'(Fig. 1) which comprises a sprocket arranged to slide relative to asupport such as the support 35 against the tension of a spring in orderthat .the chain will at all times be lkept taut to insure smooth andproper operation of the chain conveyor system. This chain conveyorsystem Vis driven by suitable m'eans such as the mo tor 58 (Figs. 3, 4and 5) which may dr-ive the chain conveyor system through suitable gears59. If desired a gear reduction means siich as a reducing gear boX maybe interposed between the motor 58 and the driving gears 59 of the chainconveyor system, if it is desired to reduce the speed of the chainconveyor.

The oven 22 is heated by a 'ow of heated air provided'by a suitableheater and blower unit such as the unit shown in general at 25. In theform of the apparatus shown in the drawings, this unit includesan oilburner 6D which may beof any suitable design. This unit also includes asuitable blowing mechanism such as that shown at 6l which is driven bythe motor 62 (Fig. 4)..

The stack 80 is provided'for use in connection with the oil burner 60.Air is drawn into thev heating and blowing unit by means of the blower6l, is heated by means of the oil burner eiland is conducted tothe ovenby means of the air duct 26.

goes through or spreads throughout the interior of the oven and thenceis removed through said air duct 63 and returns to the heating andblower unit 25 where it is reheatedand recycled back through the oven22. It will be noted,l that the return air duct 63 enters the oven atthe bottom portion thereof at two different points 64 and 62a (Figs. 1and 5) and accordingly that.the air duct 63 is divided into two sectionsin the manner clearly indicated in the drawings and in particular inFig. 5.

It will be understood that the air introduced into the oven 22 from theheater and blower unit 25 not only serves to maintain the oven at thedesired temperatures but some of this heated air ows outwardly throughthe opening 2li (Fig. 2) between the oven 22 and the chamber 2|,.-andflows upwardly through the chamber 2l and thence downwardly throughoutthe inclined tunnel 20. Thus, but a portion of the air is recycledthrough the return air duct 63.

It will be understood that the temperature of the oven 22 is readilycontrolled at suitable ther inostats located in the oven and/or withinthe air duct 26 so that the heater or blower unit is operated as desiredto producea flow of heated air into the oven at the desired temperaturesand in the desired amounts.

The operation of the present apparatus is believed lto be clear from theforegoing description of this apparatus. However, it will be readilyunderstood that the object to be treated in the present apparatus, suchas the ice trays 2l, are' hung from the bars or supports between thechains and 5l in the manner best shown in Figs. 1 and 3. They are thenconveyed through the air drying tunnel 2|), through the chamber 2 lthence several times through the oven 22 ourl of the oven 22 at thepoint i8 and are removed from vthe chain conveyor, by suitable means,when traveling from the sprocket to the point 69.

It will thus be understood that the said objects are first air dried bytraveling through the tunnel 20 and the chamber 2i and afterwards arebaked in the oven 22. By controlling the rate of speed tunnel 2|] andchamber 2l may be suitable for the particular coating utilized forprotectively coatingo the objects carried through the apparatus.

, Referring now to the various devices for removing drops from theobjects carried through the apparatus and whichare shown in Figs. 6 to13 inclusive, these devices are preferably located in the air-dryingtunnel 2l) preferably within the bottom thereof. For example, the device'shown in Figs. 6 andl'l may be positioned within the bottom 30 of theair-drying tunnel 20. This device consists of a plurality of generallyflat topped elongated' finger-like members 65-65 1 which are spacedrelatively closely together side by side on a. shaft 66. Between theseelongated members 65 are Washers 67 and the elongated members 65 arefree to move relative'to the shaft 66, but due tothe washers andthespring 68 (Fig. 7) are frictionally held on the shaft; Accorddingly,when the shaft 66 is driven, as by the motor 69, the lingers are tippedupwardly in the manner shown in Fig. 7 and are maintained inl thatposition since the shaft is free to turn rela- `covered with a suitableabsorbing material 1li such as paper or the like. After the fingers Shave been contacted by the trays moving through the tunnel 2D, they arereturned to their initial upwardly extending position by means of therotating shaft 66.

Ii" desired, a generally similar arrangement may be utilized except thatthe ilngers B5 are not motor driven to be returned, but are `so arrangedthat they return by gravity. Such a modication is shown in Figs'. 8 and9. As there shown, particularly in Fig. 9, the fingers 65 areconstructed and shaped so that the shaft is placed on center relative tothem, whereby the tray 21 will touch the top ofthe upwardly extendingtop of the fingers 65, tipping them about the shaft 55. After thelingers' 65 have been so tipped, they will return to their normalpositions through gravity due to the off-center position of the shaft 5Srelative to the pointsof the fingers 65.

Still another modification of a drop removing means is indicated in Fig.13. As there indicated,

instead of the lingers 55 there is provided a series oi spring clips 1lwhich are retained in a desired "upward generally inwardly extendingpositionl within the tunnel 2B by means of the retaining clip 12. As thetray 21 passes through the tunnel 2t it contacts the spring clip 1l,which is depressed, permitting the tray to pass through the tunnel, 2i)and at the same time removing excess drops from the .tray 21. After thistakes place, the spring clip '1i springs back into its originalposition. As in the other devices shown in Figs. 6 to 9, inclusive, thespring clip Il may contain a suitable absorbing material 10 at itscontact point.

n1 Fig. 1o there is mostrate@ sun another means for removing drops fromthe obiectsor trays conveyed through the air-drying tunnel 2B.

As thereshown, a, suitable roller 13 is provided which extends .acrossthe air-drying tunnel 29 immediately above the bottom 30 thereof. "I'hisroller is placed on a shaft 1d which in turn extends through suitablebearings 15-15 and is driven as by a motor. Also, there isv provided amember 16 which is attached in any suitable .manner beneath the roller13, such as being attaehedto the bearings 18-18 andto the bottom an ofthe air-drying tunnel zo 1n the manner mdicated in Fig. 10. Thismember'lG is bent so as to form a. tray-likel part beneathr the roller13 and may be lled with a solvent for the coating .material used on theobjects carried through the apparatus. Thus it will be seen that as theob- `jects are carried `through the air-drying tunnel Zlby the chainconveying system they are contacted by the rotating roller 13 whichremoves drops and excessive coating Vmaterial from saidobjects. As thematerial accumulates on the roller, it will be seen that the rollerrotates. through the solvent carried in the trayformed by the member'IGso that this accumulated material is `removed fromv'the roller andmay-be reclaimed later from 'the solvent.

. In Figs. 11 and l2 thereris illustrated still an-x other modicationfor removing the excess drops As the metallic objects are carried acrossthev y on the objects carried through the air-drying tunnel. This deviceconsists of a-series of electromagnets 11-11 which are positioned toextend across the width of the bottom 3d oi the airdrying tunnel 2U inthe manner shown in Fig. ll. Of course, these magnets are connected bysuitable conductors to a source of electrical energy.

ield of the magnets, it will be seen that `these magnets cause avibration of said objects and thereby shake free of the obliect allexcessive coating material or drops therefrom. Due to the inclination ofthe air-drying tunnel 2d this ma terial will dow down the bottom 3dthereof and may be removed therefrom or collected at the end thereof inany-suitable manner. It will be appreciated 'that the current sentthrough the electromagnets' is preferably alternating current, therebysetting up continuously changing magnetic fields which cause thisvibration of the trays as they pass over the magnets.

In place of or additionally to the foregoing means for removing drops orexcessive material from the objects, the bars or supports between thechains El) and 5i may be movable relative to the chains or may be formedof a resilient material, Thus the objects hung therefrom or supportedthereby are' shaken as they are conveyed through the apparatus; lfdesired, the chain conveyor may be operated intermittently at anincreased or decreased speed to' provide a series of jerky movements toaid in shaking said drops or excessive coating materialfrom the objects.

Figs. 14 and l5 illustrate modications of the present apparatusproviding for automatic dipping of the metallic articles, such as theice trays 21, in a coating mater-iai prior to the air drying and bakingoperations carried out by the present apparatus and describedhereinbefore.

Referring to Fig. 14, the modification there shown possesses anextension a of the bottom rails 34, to which upstanding frame members 8land 82 are attached by suitable means. A cross frame member 83 'extendsbetween the members di and 82 at the top thereof. To the upstandingmember 32 is attached a container 8E having a generally rearwardlyextending lip portion 85. As illustrated in Fig. 14, the chain conveyor50 instead of coming up directly to the sprocket 58a. and then extendingthrough the air drying tunnel 20, extends along the length of theextended rail 35 past the portion 35a thereof, thence about the sprocket85 upwardly aboutthe sprocket 81 and then downwardly around a sprocket88 suitably maintained within theupper portion of Y the' container Se.The chain 50 after continuing about the sprocket 88 thencontinuesout ofthe container 84 upwardly at` Van angle around the sprocket 89, thencedownwardly around the sprocket 90, over the sprocket 50a, and continuesupwardly through the air drying tunnel'20 as described hereinbefore.

.The 4container' is lined, or partially filled as the circumstancesdictate, with a coating materialto be air dried and bakedonv the articlein 'accordance with the present disclosure. Accordingly, thearticle suchas the ice trays 21 are conducted by the conveyorin the direction shownon the arrows in Fig. 14, that is, they are consprocket 89 is sopositioned relative to the sprocket 88 that the artlcles,`such as theice trays 2i, leave thecontainer` 84 on an upward incline. 'I'hisconstruction prevents one tray from dripping on the next tray which isnot desirable. Also the lip portion 85 of the container 8d is sodesigned that drippings from the trays as they leave the container 8dwill be caught and redirected back into the container 8d. It will beunderstood that the chain conveying system may be run at such a speedthat the article 2l will be conducted through the container Bd at adesired rate and will remain in said container for a suiiicient lengthof time to be coated suitably. If desired, the sprockets may be sopositioned relative to one another` that a greater path of travelthrough the container 8f3 or a lesser one is elected. Also the length oftravel of the articles 27 after they leave the container may beincreased if it is desirable to provide a greater a pair of linger-likeportions one of which is utidraining time than is shown for the devicesin the drawings.

The modification of the present apparatus shown in Fig. 15 is similar tothat shown in Fig. i4 except that the automatic dipping mechanism isseparate from the remaining parts of the apparatus and, if desired, maybe rendered portable and moved into position when it is desired to beused. Accordingly, the chain of the principal part of the apparatusshown at 5K0 goes about the sprocket 50a and thence through the tunnel2d in the manner described hereinbefore and as shown in Fig. 1. There isprovided a separate chain si and an additional sprocket t2 so that thechain 9i forms a separate continuous chain system running about theysprocket a2 to the sprocket 8, thence to the sprockets Si, da, E@ and9d. It will be understood that there is a similar chain on the otherside of the device and that these chains are connected by spring bars inthe manner described herelnbefore. On these spring bars the articlessuch as the ice trays @i are hung by a particular type of hook @3.

lized to hold the hook onto the spring bar and the other of whichxtendsin the direction of air tunnel 2d. Accordingly,l when the pans 2? havebeen carried through the container all and coated, they areautomatically transferred from a spring bar on the chain Si to one onthe chain 5@ ofthe principal part of the apparatus, in the mannerclearly shown in Fig. i5. 0f course it will be understood that the chain@t is driven by a suitable means (not shown) and that the speed of thechain 49i is synchronized with the `speed of the chain 5d so that thepans or other articles will be transferred automatically from the chain9i to the chain 5t and thence conveyed through the remaining parts ofthe apparatus.

We claim: Apparatus for air drying and baking a protec= "tive coatingfor metallic articles 'subject to corr@ sion, which comprises arelatively elongated air conducting drying tunnel, a plurality of memrsarranged on a shaft extending across said tunnel for removing excessivecoating material from said articles, each of said members being shapedto project into the tunnel for contacting said articles and beingmovable on said shaft on such contact so that the articles depress themembers, an air conducting drying chamber communicat ing with saidtunnel, a baking chamber commu-- nicating with said drying chamber, afurnace for producing a flow of heated air, a V.duct for directim saidheated air into 'said mi chamber, air. blowing means for-forcing saidair through said baking chamber into said drying n. 1t.- and into saidtunnel, and a. continuous conveyor for conducting the articles throughsaid tunnel through said air-drying chamber and thence through said .iwfchamber, whereby a coating on said arti es is air drim and `thereafterbaked.

